Warning: long post, because I'm tired and kind of irked.
> "Not to mention that the pure and "non religion like" idea of Buddhism that westerners have is not at all how it works for common people in China or asia in general."
I'm Chinese. Please do not seek to describe my own culture back to me with Wikipedia.
For one thing, I object strongly to the use of "shenism" - it's as much an "ism" as "Westernism" is an "ism". It's an umbrella to try to catch entirely dissimilar and wildly variable things all in one bucket, and it implies a level of coherence that simply does not exist. The folk religions of China wildly vary depending on people and region, and to try and slam it all into an "ism" makes about as much sense as trying to corral all Native American beliefs into the umbrella "Aboriginism". "shenism" transliterates into "deism". How much sense does that make to you?
Reading Wikipedia articles on Chinese religious belief is like reading a terrible social sciences textbook from high school. It captures none of the context and none of the spirit of what is actually worshipped. Instead it's just a purely academic account with purely academic distinctions drawn between things.
> "Even confucianism serves the role of religion, with several societal norms and guidelines etc."
This has always been a vibrant topic of debate in Chinese society, and I'm surprised you can confidently say that when no one who practices it can seemingly agree. Confucianism lacks the hallmarks that identify other religions (including ones practiced in China) - most notably the complete lack of deities, or in fact any belief in the supernatural.
Most adherents seem to regard it as a philosophy and cultural imperative (given its dominance of Chinese intellectualism over history) rather than a religion. The need to label it as a religion, in fact, seems to derive from Western inability to categorize it in their world view.
IMO if we start classifying Confucianism as a religion, then we need to throw democracy, libertarianism, communist, and capitalism into the religion pot too.
> "Buddhism in China is _one_ of several religions. Taoism, Shenism, etc, are as prevalent."
Indeed. Well, not really, sort of. It's complicated. Traditional Buddhism and Taoism are relatively rare amongst the general population, though has gained more traction in recent times. Most people adhere to a mish-mash of Buddhist thought, Taoist belief, and what you describe as "shenism", not one of the above. This giant religion-gumbo more or less deserves its own name, but we really don't have a good word for it. An important side effect of this is that religion in Chinese society is largely grassroots and disorganized (well, until the introduction of Judeo-Christian thought). You will find people worshipping Buddhist deities (or deified Buddhist not-deities) right alongside traditional folk deities, using rituals that are not at all similar to what you might find in original Buddhist scripture.
Wikipedia tries to characterize this as "shenism", though as previously mentioned, this is a nonsense concept. Though I would not be categorically opposed to finding a word for "that crazy mix of Buddhism, Taoism, and local geocentric folk religions that is practiced in various ways in China" - bit of a mouthful after all. Only if they choose a word that's less stupid than "shenism". "Shenism" is not a coherent religion, and as currently defined just means "people that believe in deities in China".
In any case, this is a very roundabout way of addressing your point:
> "Actually religion predates most forms of even government and cultural practice."
Which means... exactly what? My contention is the marriage as practiced in China is not primarily a religious event. It features no priests, no church steeples, nor synagogues, nor mosques. It features no overarching religious motif, though it is common for various aspects of folk religion to manifest as ancillary rituals - folk religions that lack any form of organization and scripture, mind you. No religious figures are present - neither priest nor monk. In fact, none of the major components of Chinese marriage, from proposal to tying the knot, are religious in nature, nor do they even have hints of religious meaning.
If Chinese folk religion created the institution of marriage, then why is it none of the entire process involves religious worship of any sort? In fact, if it's primarily a religious exercise, why is it that the rituals and traditions are pretty much all the same even for traditional Buddhists and Taoists? Or perhaps, alternatively, marriage in China is primarily a cultural institution, where religious motifs are applied, removed, and changed over millenia to suit the religious mores of its time?